Automatic stoker



1,636,375 July 1927' LVUNDGREN AUTOMATIC STOKER med July 27. 1922 sSheets-Sheet 1 Wm I INVENTbR.

- I ATTORNEYS. I I I'll 5 I I E. LUNDGREN AUTOMATIC STOKER Filed July27. 1922 s Sheets-Sheet z A7777 Wm July 19, 1927.

E. LUNDGREN AUTOilATIC swoxn'n Filed July 27. 1922 :s Sheqts-Sh6iet sINVENTOR.

' ATTORNEYS.

Patented July 19, 19,27.

UNITED STATES PATENT OFFICE.

EDWIN 'LUNDGREN', OF FREDERICK, MARYLAND, 'ASSIGNOR TO COMBUSTION ENGI-NEERING- COBPORATION, OI NEW YORK, N. Y., A CORPORATION OF NEW YORK.

, AUTOMATIC sroxnn.

Application filed July 27,

The present invention relates to furnaces or stokers of the type inwhich the fuel while in the course of combustion is fed progressivelytoward a discharge outlet through which the refuse of the fuel isautomatically discharged.

An object of the invention is to provide a novel and improved furnace ofthis charac- 1'61.

Another object of the invention is to provide novel and improved meansin a furnace of this character for insurin the complete combustion ofthe fuel be ore being discharged.

Another object of theinvention is to provide novel and improved refusecrushing and expelling means for a furnace of this character.

lVith these and other objects in view, the features of theinventionconsist in certain constructions, arrangements and combinationsof parts hereinafter described and claimed, the advantages of which willbe obvious to those skilled in the art. 7

The several features of the invention will be clearly understood fromthe following description and accompanying drawings, in which,-

Figure 1 is'a plan view, partly in section and with some of the saidmetal plates conslituting component parts of the refuse dischargingmeans hereinafter described removed, of a portion of a furnace of theunder-feed type embodying the features of the invention in theirpreferred form;

Fig. l is a transverse sectional view, on an enlarged scale, taken onthe line 2-42 of n- Fig. 3 is a detail sectional view taken on the line3-3 of Fig. 1;

Fig. 4 is a similar view showing a modilied construction of clinkercrushing and expelling means; and

Fig. 5 is a sectional view, taken on the line 5-5 of Fig. 4.

The furnace illustrated in the drawings is provided with an underfeedsection 2, and an overfeed section 4 at the rear of the underfeedsection. The underfeed section comprises a series of downwardly andrear-' wardly inclined retorts 6 arranged side by side and spaced apartand the outer walls of the outer retorts are spaced from the side wallsof-the furnace, with inclined rows of tuyere blocks 8 spanning thespaces between 1922. Serial No. 577,823.

the margins of adjacent walls of the retorts,

and the margins of the outer walls of the outer retorts and the sidewalls of the furnace. Reciprocating plungers are mountr ed in theretorts, or other suitable means may be provided for progressivelyfeeding the fuel from the retorts while in the course of combustion anddischarging the refuse of the fuel from the grate sections. The overfeedgrate section 4 comprises a plurality of grate bars 9 arranged side byside and curved downwardly and rearwardly.

The illustrated construction is also provided with a novel and improvedrefuse crushing and expelling roll 10, and an apron 11. whichconstitutes a portion of the rear wall of the ash pit of the furnace,the roll and apron having cooperating clinker crushing teeth 12 and 13,respectively. The clinker crushing roll is mounted on a hollow shaft 14having its ends journaled in bearings on beams or hangers 16 arrangedadjacent the side walls of the furnace. One end of the hollow shaft 14is closed and its other end is open and is connected by a swivel jointwith a conduit 18 to which air is supplied under pressure by suitablemeans, the supply of air to the hollow shaft 14 being controlled byadamper 20in the conduit 18.

The shaft 14 is driven in a clockwise direction by any suitable means asby a worm wheel 22 secured thereon which is operatively engaged by aworm 24 carried by a driving shaft 26.

The clinker crushing roll 10 which is of relatively large diameter is ofhollow construction and made up of sections that are arranged end to endas shown in Fig. 1.

Each section of the roll 10 is divided into three segmental compartments28 that together completely surround the hollow shaft 1.4. The innerperipheral wall of each compartment is provided with a rectangularaperture 30 which registers with a similar aperture 32 in the hollowshaft 14 so as to provide communication between the several chambers andthe shaft. Gravity actuated clapper valve members 34 are pivotallymounted at one end on the interior of the hollow shaft 14 and areassociated with the apertures 32. respectively. so that as a compartment28 approaches its lower position during the rotation of the roll 10 theclapper .valve member 34 will close communication between thecompartment and the hollow shaft 14 and as the compartment approaches 7its uppermost position the clapper valve member will swing down bygravity and thus open communication between the compartment and thehollow shaft 14. For c0n venience'in assembling, each section of theroll 10 is divided into two longitudinally extending segmental parts 38and 40, the part 38 containing one of the compartments 28 and the part40 containing the other two compartments 28, this part 40 being providedwith a radially extending partition 42 separating the compartments.These two parts 38 and 40 are detachably secured together by clampingbolts 44 which extend through apertures in adjacent radially extendingwalls 46 of said parts, thus enabling the parts of each section to beeasily assembled and taken apart.

The outer peripheral wall of each of the compartments 28 is providedwith a series of tircumferentially extending spaced apertures 47, theapertures of the'several compartments being in circumferentialalinement, respectively. Each of the apertures 47 in'the outerperipheral wall of the compartments 28 is covered by a segmental plate48. The plates 48 associated with corresponding apertures of the severalcompartments are arranged end to end so as to embrace the drum, theseries of plates associated with the apertures of each compartment 4being held spaced apart by spacing bosses 50 on the edges thereof. Theunder sides ofthe segmental plates 48 are provided with radiallyprojecting herring-bone or V-shaped ribs 52 which are spaced apart. Theplates 48 prevent the peripheral apertures 47 from becoming clogged bythe refuse of the fuel and prevent the refuse' from sifting through theapertures, a free passage for the air from the several compartments 28being provided through the apertures 47 and the spaces between the ribs52, the herring-bone shape of the ribs 52 obviating any danger of thespaces between them becoming clogged.

The segmental plates 48 are adapted to be easily applied to and removedfrom the drum 10 without removing the drum or drum sections from theshaft 14 and without remov-' ing the shaft from its bearings. To providefor this each section of the drum is provided with a plurality ofT-shaped rails 54 extending longitudinally thereof and the ends of thesegmental plates 48 are provided with transverse grooves 56 which areadapted to fit over opposed laterally projectin ribs 60 on the rails andthus securely lock t e plates on the drum, the plates being applied bysuccessively sliding them over the rails from one end of the drumsection and the correct spacing of the plates being determined by thespacing bosses 50 on the edges of the plates. The right handend portion,viewmg Fig. 1', of corresponding locking ribs 60 nesaers of the rails iscut an .iy as indicated at 59 so as to enable the segmental plates to heslid into position from this end of the drum tions without disturbingthe position of the sections, each plate being applied by engag ing oneof its grooved ends with its locking rib 60, then swinging the platedownwardtv to bring its opposite end in said cut away portion of theopposed locking rib and then sliding the plate longitudinally of therails into its final position. The right hand series of segmental plates48 of each drum section are held in place by bolts 61 which extendthrough apertures in the plates and are screw-threaded into the drumsectipn. The clinker crushing teeth 12 of the drum are formed on thesegmental plates 48. mm the foregoing it will be apparent that eachsection of the clinker crushing roll or drum may be easily taken apartand assembled without disturbing the other sections or removing theshaft of the roll from its bearm s.

The clinker crushing drum or roll 10 is arranged with the top portion ofits surface substantially on the level of the lower end of the overfeedgrate section, and 18 of. sufficiently large diameter to enable itsforward portion to extend closely adjacent to and slightly forwardly ofthe lower end of the supporting surface of the overfeed section, and itsrear portion to extend sufficiently close to the apron 11 to enable itscrushing teeth to effectively cooperate with the crushing teeth of theapron.

Heretofore it has been considered necessary' in furnaces employing aclinker crush ing roll to provide a deep ash pocket and to mount theroll near the bottom of the ash pocket so that the ashes in the pocketwill protect the roll from injury from the heat of the fuel bed. It willbe apparent, however, that although my improved clinker crushing roll islocated close to the burning fuel, it is so constructed that the coolair' admitted to its interior and discharge through apertures in theupper portion of its peripheral wall at all times during its operation,effectively prevents the roll from becoming overheated. It will also beapparent thatthe large refuse supporting area of the clinker crushingroll and the discharge of air therefrom not only insures the propercooling of the refuse but also ensures the complete combustion of anyunconsumed fuel passing the grate sections 2 and 4, the roll thusserving as an additional grate section.

The apron 11 above referred to is made up of a plurality of sectionscorresponding in number and arranged opposite to the sections of theclinker crushing roll or drum 10.

lil)

is closed and its other end is in communication with a suitable sourceof water or steam supply through a valve 72. The upper 012. tion of eachsection of the apron 11 is of ox like construction and its forward wallis provided with apertures 78 through which water or steam is adapted tobe directed from the pipe 66 which is provided with perforations 80. Thesaid box-like portion of each'section of the apron is in communicationwith an air supply chamber 82 through an opening 84: in the bottom wallof the chamber which registers with an opening 86 in the upper end wallof the section, the air being directed into the furnace through theapertures 78. The air chamber 82 is made in sections corresponding innumber and arrangement to the sections of the apron. The severalsections of the chamber are in communication with each other through reistering apertures 88, and the chamber is a apted to receive air underpressure through a pipe 90 at one end, the supply of air-to the chamberbeing controlled by a damper 92 mounted in the pipe. The forward wall ofthe several sections of the air chamber 82 is provided with tuyereopenings 94 for directing air into the furnace.

Each section of the apron 11 extends a considerable distance below itspivot and its lower end is so weighted that under normal conditions ofoperation the apron will offer suflicient resistance to being swung backfrom the clinker crushing roll to enable its clinker crushing teeth toeffectively cooperate with the teeth of the roll, but in case a clinkershould be acted upon that cannot be broken by the teeth of the roll andapron, the section of the apron engaged. by the clinker will yield orswing back sufiiciently to permit the clinker to drop down into the ashpit, this construction preventing injury to the parts of the clinkercrushing devices. To obviate any danger of the teeth of the apron beingbrought into the path of the teeth of the roll, spring buffers areprovided, for limiting the forward swinging movement of the sections ofthe apron. Each of these spring buffers comprises a rod 98 having oneend pivotally connected with a section of the apron and its other endextending through an aperture in the I-beam 70, and a spring 99 coiledabout the rod and interposed between the I-beam and a washer and nuts100 on the end of the rod. As shown in Fig. 1, each of the sections ofthe clinker crushing roll 10, apron l1 and air chamber 82 corresponds inlength to the distance between the axes of adjacent rows of tuyereblocks 8, which construction is desirable as it enables the stoker to beeasily increased and decreased in width by increasing or decreasing tlienumber of said sections, retorts 6, rows of tuyere blocks 8 and overfeedgrate bars 9.

The clinker crushing roll illustrated in Figs. 4; and 5, instead ofbeing mounted on a hollow shaft through which air is supplied to theroll is mounted on a solid shaft- 102 and the air is supplied to theroll through a conduitlOet extending, through a side wall of the furnaceand having its end flush with the side wall. divided by radiallyextending partitions 106 into six compartments and the end wall of theroll is arranged closely adjacent to said side wall and is provided withopenings 108 leading into said compartments, respectively. The air suply conduit 104 is arranged above the axis 0 the roll and the openings108 are so arranged as to be successively brought into registry with theair supply conduit during the rotation of the roll so as -to cause Theinterior of the roll is.

air from the air supply conduit to be directed I through the airpassages in the peripheral wall of the roll as they approach theiruppermost position and to be shut off from the air passages as theyapproach their lowermost position.

As will be evident to those skilled in the art my invention permits ofvarious modi-' fications Without departing from the spirit thereof orthe scope of the appended claims.

VVhatI claim is: 1. .A furnace having, in combination, means forsupporting and feeding fuel while in the course of combustion and fordelivering the refuse of the fuel therefrom, and refuse expelling meanscomprising a rotatable drum of hollow construction, having asubstantially cylindrical refuse supporting surface having clinkercrushing teeth thereon, arranged to act on the refuse as it leaves saidsupportingineans and having air ducts leading out t rough its peripheralwall, and means acting automatically during each rotation of the drum todirect air through ill) those of said air ducts approaching the top i ofthe drum and shutting it off from those of said air ducts approachingthe bottom of the drum.

2. A furnace having, in combination, means for supporting and feedingfuel while in the course of combustion and for delivering the refuse ofthe fuel therefrom, and refuse expelling means comprising a rotatabledrum of hollow construction, having a substantially cylindrical refusesupporting surface having clinker crushing teeth thereon. arranged toact on the refuse as it leaves said supporting means, having air ductsleading out through its peripheral surface and having its interiordivided radially into a plurality of air chambers, and means comprisingan air supply conduit for autoi'natically supplying air to and shuttingit oif from said 3. A furnace having, in combination, means forsupportin and feeding fuel while in the course of com ustion and fordelivering the refuse of the fuel therefrom, and refuse expelling meanscomprising a rotatable drum of hollow construction arranged to act onthe refuse as it leaves said supporting structed to be opened by gravityas they approach the top of the drum and to close by gravity as theyapproach the bottom of the drum.

4. A furnace having, in combination, means for supporting and feedingfuel while in the course of combustion and for delivering the refuse ofthe fuel therefrom, and refuse expelling means comprising a rotatabledrum of hollow construction arranged to act on the refuse as it leavessaid supporting means, and having openings in its peripheral wall, andmembers covering said openings and provided-with laterally extendingribs spaced apart and engaging the periphery of the drum to enable airafter passing through said openings to pass out through the spacesbetween said ribs, and means for supplying air to the drum and forrotating the drum.

5. A furnace having, in combination, means for supporting and feedingfuel while in the course of combustion and for delivering the refuse ofthe fuel therefrom, and refuse expelling means comprising a rotatabledrum of hollow construction arranged to act on the refuse as it leavessaid supporting means, having openings in its outer wall aranged incircumferential alinement, and

segmental members arranged end to end so as to surround the drum andcovering said openings with their inner surfaces provided wlth laterallyextending ribs to enable air after passing through said openings to'passout through the spaces between said ribs, means for detachably securingsaid members to thedrum, and means for supplying air to and for rotatingthe drum.

6. An underfeed furnace having, in combination, an undcrfeed gratesection, an overfeed grate section inclined downwardly and reawardlyfrom the undcrfeed section, an

ash pit at the rear of the overfeed section having its rear wallprovided with clinker crushing teeth, a rotatable refuse crushing andexpelling drum of relatively l arge dianr eter having its top surfaceportion arranged substantially on the level of the lower end of theoverfeed section, its forward portion arranged closely ad acent thelower end of the overfeed section and its rear portion sufficientlyclose to the rear wall of the ash pit to enable its teeth to co-operatewith the teeth of said wall of the ash pit, said drum being of hollowconstruction and having apertures leading out through its peripheralwall, and means for rotating the drum and for supplying air to theinterior thereof.

7. A furnace having, in combination, means for supporting and feedingfuel while in the course of combustion and for delivering the refuse ofthe fuel therefrom, refuse expelling means comprising a roll havingclinker crushing teeth arranged to act on the refuse as it leaves saidfuel supporting means, and a pivotally mounted apron spaced from and atthe opposite side of the roll from said fuel supporting means andprovided with clinker crushing teeth arranged to co-operate with theteeth on the roll, the upper portion of said apron being of hollowconstruction and having apertures leading out through its exposed wall,and means for supplying air to the interior of said hollow portion ofthe apron.

8. A furnace having, in combination, means for supporting and feedingfuel While in the course of combustion and for delivering the refuse ofthe fuel therefrom, refuse expelling means comprising a roll havingclinker crushing teeth arranged to act on the refuse as it leaves saidfuel supporting means, an apron spaced from and arranged at the oppositeside of the roll from said fuel supporting means and having a portionthereof of hollow construction having its exposed wall provided withapertures, and a fluid conducting pipe on which the apron is pivotallymounted having apertures opening into the interior of said hollowportion of the apron.

9. A- furnace having, in combination, an underfeed grate sectioncomprising a plurality of retorts and rows of tuyere blocks alternatelyarranged, an ash pit arranged at the rear of said grate section forreceiving the residue of the fuel, a clinker crushing roll mounted inthe ash pit, a pivotally mounted apron of hollow constructionconstituting a portion of the rear wall of the ash pit and an airchamber in communication with the interior of the apron, said clinkercrushing roll, apron and air chamber being each made/in sections, eachsection corresponding in length to the distance between the axes ofadjacent rows of tuyere blocks so as to permit the width of the fur-.nace to be easily increased and decreased.

10. A furnace having, in combination, means for supporting and feedingfuel while in the course of combustion and for delivering the refuse ofthe fuel therefrom, andrefuseexpelling means comprising a rotataoledrumof hollow construction arranged to act on the refuse as it leavessaid supporting means. and having air ducts leading out through itsperipheral surface. a hollow shaft on which the drum is mounted, meansfor directing air into the interior.- of said shaft, and. means actingautomatically duringeach rotation of the drum to open com municationbetween the interior of the drum and those of said air ducts approachingthe. top of the drum, and to close conin'mnieation between the interiorof said shaft and those of said air ducts approachingr the bottom of thedrum.

11. A furnace having, -in combination,

means for supporting and feeding fuel while in the course of combustionand for delivering the refuse of the fuel therefrom. and refuseexpellingmeans comprising a rotatable drum of hollow construction arranged to acton the refuse as it leaves said supportingmeans, having air ductsleading -out through its peripheral surface and having radiallyextending partitions dividing the interior of the drum into a pluralityof air chambers, a hollow shaft on which the drum and to closecommunication with said air chamber as it approaches the bottom of thedrum.

12. An underfeed furnace having, 111 c0mhination. an underfeed gratesection, an.

orerfeed grate section at the rear of the underfeed section, an ash pitat the rear of 'the orerfecd section, and refuse expelling and crushingmeans comprising a rotatable drum of hollow construction mounted in theash pit and arranged to act on tlllefllse as it leaves said overfeedgrate section, and having air ducts leading out through its peripheralWall, and means acting automatically during each rotation of the drum todirect air through those of said air ducts approaching the top of thedrum and to shut it off from those of said air ducts approaching thebottom of the drum.

EDWIN LUNDGREN.

